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Camera Backend Dependencies

This document lists all system and Python dependencies required for the camera backends.

System Requirements

Hardware

  • Raspberry Pi 5 (or compatible)
  • Camera modules (tested with Arducam IMX519)
  • Raspberry Pi OS Bookworm (64-bit)

Operating System Packages

Required for Both Backends

sudo apt-get install -y \
    python3-dev \
    libcap-dev
Package Purpose Required For
python3-dev Python development headers Building Python C extensions
libcap-dev libcap development headers python-prctl dependency

Required for Picamera2 Backend Only

sudo apt-get install -y \
    python3-libcamera \
    python3-kms++
Package Purpose Version Tested
python3-libcamera Python bindings for libcamera 0.5.2+125
python3-kms++ KMS++ Python bindings 0~git20250807

Required for Subprocess Backend Only

# Already installed on Raspberry Pi OS with camera support
rpicam-apps  # Provides rpicam-still command

Python Dependencies

Core Dependencies (requirements.txt)

All listed in requirements.txt - installed via pip:

pip install -r requirements.txt

Camera-Specific Dependencies

picamera2>=0.3.33  # For picamera2 backend

Dependencies of picamera2 (auto-installed):

  • numpy>=2.4.0 - Array operations
  • pillow>=12.1.0 - Image processing
  • piexif>=1.1.3 - EXIF metadata
  • simplejpeg>=1.9.0 - Fast JPEG encoding
  • python-prctl>=1.8.1 - Process control (requires libcap-dev)
  • PiDNG>=4.0.9 - DNG RAW format support

Virtual Environment Setup

Critical: System Package Linking

The picamera2 backend requires access to system-installed libcamera Python bindings, which cannot be installed via pip. The virtual environment must be configured to see system packages:

# Create venv
python3 -m venv .venv

# Link system packages (REQUIRED for picamera2 backend)
echo "/usr/lib/python3/dist-packages" > .venv/lib/python3.11/site-packages/system-packages.pth

# Activate and install
source .venv/bin/activate
pip install -r requirements.txt

Automated Setup

Run the setup script to handle all dependencies:

./setup_camera_backends.sh

This script will:

  1. ✓ Check system compatibility
  2. ✓ Install system packages
  3. ✓ Create/update virtual environment
  4. ✓ Link system site-packages
  5. ✓ Install Python dependencies
  6. ✓ Verify installation

Verification

Test that all dependencies are correctly installed:

source .venv/bin/activate

# Test system bindings
python -c "import libcamera; print('libcamera OK')"

# Test backends
python -c "from capture.backends import RpicamBackend, Picamera2Backend; print('Backends OK')"

# Run full test suite
python capture/test_phase2_picamera2.py

Docker Considerations

For containerized deployments, the Dockerfile must:

  1. Install system packages:
RUN apt-get update && apt-get install -y \
    python3-dev \
    libcap-dev \
    python3-libcamera \
    python3-kms++ \
    rpicam-apps
  1. Grant camera access:
# Add to docker-compose.yml
devices:
  - /dev/video0:/dev/video0
  - /dev/video1:/dev/video1
privileged: true  # Required for camera access
  1. Link system packages in container:
RUN echo "/usr/lib/python3/dist-packages" > \
    /app/.venv/lib/python3.11/site-packages/system-packages.pth

Troubleshooting

Issue: python-prctl fails to build

error: command 'gcc' failed with exit code 1

Solution: Install build dependencies

sudo apt-get install -y python3-dev libcap-dev

Issue: ModuleNotFoundError: No module named 'libcamera'

Solution: Link system packages to venv

echo "/usr/lib/python3/dist-packages" > \
    .venv/lib/python3.11/site-packages/system-packages.pth

Issue: Camera access denied

Solution: Add user to video group

sudo usermod -aG video $USER
# Log out and back in

Dependency Update Policy

  • System packages: Follow Raspberry Pi OS updates
  • Python packages: Pin versions in requirements.txt
  • libcamera: Tied to system package version
  • picamera2: Pin to tested version (currently >=0.3.33)

References
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